1. Field of the Invention
The present invention relates in general to power converters and more particularly, to a solar inverter circuit that: (i) converts direct current (DC) power from a solar photovoltaic array to a counterflowing alternating current (AC) power in response to a reference AC power source, and (ii) generates additional AC power to supplement the reference AC power source.
2. Background of the Related Art
Conversion of direct current (DC) power from solar cells to alternating current (AC) power required in residential AC lines usually employs a large number of batteries for storing DC electrical energy from solar cells during day-time. The batteries serve as a DC voltage source. The DC voltage source is then converted to simulate sinusoidal ac voltage by a number of methods. One such method uses an asynchronous sine-wave generator or a digital technique to mimic an AC voltage having a plurality of DC levels. To couple such converted AC voltage to the residential AC line, the phase, frequency and amplitude of the converted AC voltage must be the same as that in the residential AC line. If these parameters are not synchronized, serious problems to the municipal electrical supply, and/or to the converted solar source would result.